GREAT BARRINGTON — Water tests at Walter J. Koladza Airport last month found lead concentrations well below the level of concern.

But the results of the test, taken from a faucet in the airport office, and from a well beneath it, are unlikely to put to rest lead contamination fears that have kept a proposed airport construction project in a holding pattern.

"Lead is not an issue," said airport Manager Kenneth Krentsa, pointing to the test results.

Some airport neighbors, however, say they have elevated levels of lead in their drinking water, which they believe might be from airplane fuel. Testing of water at two nearby households found lead levels well above what the U.S. Environmental Protection Agency says is the level that requires action, 15 parts per billion.

The EPA says given the "best available science," there is no safe level for lead exposure, a heavy metal that is toxic to the nervous systems and organs of humans and animals.

The airport had water and soil testing done at the behest of the Select Board, which is trying to get a handle on whether there is a problem ahead of yet another public hearing on the airport project. That hearing will begin at 6:30 p.m. Monday in Town Hall.

Results of the soil tests were not available.

The airport's owner, Berkshire Aviation, is seeking a town permit for zoning compliance that would allow it to build three new hangars in a residential/agricultural area that also happens to be a water supply protection district.

Neighbors for months have fought the permit. They raised safety concerns. They complained of noise and flight patterns. And they said the proposed location of the new hangars would block pastoral views.

Most recently, concerns have shifted to the aquifer, especially after residents learned that many small aircraft still use leaded aviation gas. It's something the FAA says is a major source of airborne lead emissions, particles of which the EPA says can eventually get into groundwater, depending on the type of soil and other factors.

Lead concentrations in samples taken from the well and a bathroom faucet in the airport's office tested at 1 part per billion, well below the EPA action level. Culligan Water took the samples, and those were tested at Microbac Laboratories in Lee — the same company that tested the neighbors' water.

The well is directly under the airport office, and is 8 to 10 feet deep, according to employee Joseph Solan, the son of airport owner Richard Solan.

But neighbors who live along Seekonk Cross Road, which abuts the airport on one side, also have had their wells and faucets tested. Two report concentrations of lead well above acceptable levels; a third showed slightly elevated levels that, while still acceptable, had doubled in two years.

One of the homeowners points to contamination in the aquifer, because he said could not find other sources of lead on his property.

While they all worry aviation gas is the culprit, finding the source of lead in water isn't always easy.

"Lead is a challenging one because you have multiple sources," said Brian Oram, a Dallas, Pa.-based geologist and environmental consultant who started the Water Research Center.

Oram said some materials used in well construction have low levels of lead, but had higher levels in the old days. And he said having a new house with PVC pipes doesn't necessarily eliminate lead.

"Faucets have some lead in them — a 'lead-free' faucet doesn't mean there's no lead," Oram said.

And there are other factors like how often water moves through the pipes, and bacterial or other problems that can make water more corrosive to pipes, which causes lead to seep in. He said bacteria can also pull lead — even naturally occurring lead — out of the water source.

Despite all this, the airport is under the microscope. In a May letter to the Select Board, neighbor Anne Fredericks wrote that the "state testing lab informed us that it was 'highly irregular' to find lead in an aquifer." Hers was among the two homes with high levels of lead.

She also wrote that while there is no direct evidence the airport is the source of trouble, she cited a state report that says the airport is one of a number of threats in the area to the aquifer.

But the town water department isn't worried. In a letter to Berkshire Aviation's attorney, the Prudential Committee said its water supply gallery is more than a mile away, and storing aircraft in hangars with concrete floors will lower the risk that fuel or other fluids might leak from an airplane and into the soil, where about 50 aircraft are usually tied down when not in use.

The town water department's most recent 2015 lead results were well below the EPA's action level.

Whatever happens with the permit, the airport might still have a bunch of rules attached to it. Fredericks and her husband, Marc Fasteau, have been pushing for conditions like selling a new lead-free fuel along with the existing fuel that many planes still require, until leaded fuel is banned altogether in the next few years.

The airport sells the leaded fuel, and while the underground tank has a monitoring system, it has to be replaced this summer because it is 20 years old. Krentsa said it would be replaced with an above-ground tank.

Standing near the self-serve fueling area, Krentsa — who often grows frustrated at what he says is a manufactured controversy — looked at the office building where the water samples were taken.

"It's 200 feet from the building," Kretnsa said of the tank's proximity to the well.

Krentsa acknowledged it isn't just this tank the neighbors are worried about, and said the soil testing was a good idea.

"It will at least give us information," he added. And he also noted other nearby threats to the water supply.

"We are surrounded by farms that use all kinds of pesticides and who knows what else," he said.

Reach staff writer Heather Bellow at 413-329-6871.